WO2005049298A1

WO2005049298A1 - Forming and moulding tools and method of manufacture thereof

Info

Publication number: WO2005049298A1
Application number: PCT/AU2004/001628
Authority: WO
Inventors: Periklis Christodoulou
Original assignee: Qmi Solutions Limited
Priority date: 2003-11-24
Filing date: 2004-11-24
Publication date: 2005-06-02

Abstract

A forming or moulding tool (10) having a composite forming or moulding surface (12) defined by a plurality of shaped sheet panels (14), each having a forming or moulding surface (15) and a support structure for the sheet panels (14) comprising a plurality of wall panels (16) and (17) arranged in a grid-like configuration and which are complementary to the underside of the sheet panels (14). Chambers (18) beneath the shaped panels (14) may be filled with a foam material or liquid to provide additional support to the panels (14). A method of manufacture of the tools is also disclosed.

Description

FORMING AND MOULDING TOOLS AND METHOD OF MAN UFACTURE THEREOF

Technical Field

This invention relates to forming or moulding tools particularly suited to use in moulding of large size objects but which are also applicable to the moulding of smaller size objects. The present invention also relates to a method of manufacture of forming or moulding tools and a method of moulding using the tools.

Background Art

Forming or moulding tool$ are used in many applications including applications in closed moulding processes where articles produced in the processes have their external surfaces as finished surfaces. An example of a closed moutding process is the moulding of resin fiber reinforced composite parts in. which resins are injected into a mould cavity filled with or containing fiber mat. Typical processes of this type include Resin Transfer Moulding (RTM) and Reactive Injection Moulding (RIM), Conventional injection moulding processes can be used for the production of both small and large components, however tooling costs becomes prohibitive for larger size mouldings. The costs of tooling for large size components is usually then only justified if the production run is sufficient to enable the tooling costs to be economically amortised.

Forming or moulding tools are also used in open moulding techniques where it is more likely larger size components or articles will be manufactured. Typical of such articles are watercraft which are moulded of glass reinforced plastics, ϊn the manufacture of watercraft using this method, a number of different steps are involved in producing the tool or mould. A male plug is initially required to be constructed which defines the shape of the article to be moulded such as the hull and/or deck of a watercraft and then a female tool or mould is constructed using the male plug to define the shape of the mould cavity. These large size moulds or tools are relatively expensive and take a considerable period of time to construct and because of their size are usually difficult to handle. Further tools of this type have a limited operational life. Forming and moulding 'tools are also used in many other manufacturing applications such as in thermofor ing, vacuum foπning or rotational moulding using various plastic or plastic composite materials to form components. Suitable tools or moulds for these applications also can be relatively expensive and time consuming to construct,

Summary of the Invention

The present invention aims to provide foπning or moulding tools which overcome or alleviate one or more of the above disadvantages or which at least provides a viable and effective alternative to the known forming and moulding tools. The present invention also aims in a further aspect to provide a method of manufacturing foiming or moulding tools. The present invention in yet a further aspect aims to provide a method of forming or moulding using the forming or moulding tools of the invention.

The present invention thus provides in a first aspect, a forming or moulding tool having a forming or moulding surface defined by at least one shaped sheet panel and support means for supporting said sheet panel and thereby said forming or moulding surface.

The support means for the at least one sheet panel may comprise mechanical and/or fluid supporting means arranged on the side of the sheet panel remote from the forming surface. The mechanical support means may comprise an egg-crate support for supporting the sheet panel at a plurality of locations. The mechanical support means may additionally or alternatively include a foam material such as a foam plastics, a metal foam or a ceramic foam. The mechanical support means however may comprise any other mechanical supporting arrangement which will support the sheet panel on its side opposite the fonning or moulding surface in such a manner as to maintain its rigidity and stability during a moulding or forming process using the forming or moulding tools.

The egg-crate support suitably comprises a plurality of supporting elements arranged in a grid. Each supporting element suitably has an edge or surface complementary to portion of the side of the sheet panel opposite the forming or moulding surface such that the portion of the sheet panel may be supported continuously along the edge or surface of the supporting element. The supporting elements for the or each sheet panel may comprise at least a first supporting element and a second supporting element extending substantially normal to the first supporting element Preferably the first and second supporting elements intersect or meet each other. Most preferably there are provided a pair of spaced apart first supporting elements and a pair of spaced apart second supporting elements, the elements of each pair suitably extending substantially parallel to each other. Preferably the or each sheet panel is rectangular such as by being square in plan view and the first and second pairs of supporting elements are arranged to extend along and support the sheet panel at or adjacent the side edges thereof. Further intermediate supporting elements may be provided between the elements of the first and second pairs to engage the sheet panel on its side opposite the forming or moulding surface to support intermediate portions of the sheet panel. The sheet panel is suitably secured continuously along its side edges to the respective supporting elements of the first and second pair. The sheet panel may be secured continuously to the further supporting elements or at spaced positions to the supporting elements. Typically the sheet panels and supporting elements are formed of metal such as aluminium and the sheet panels are secured to the supporting elements by welding. The combination of a sheet panel and first and second pairs of supporting elements (with or without the intermediate supporting elements) suitably forms a tool module.

The sheet panel and supporting elements therefore suitably define a chamber or chambers on the side of the sheet panel opposite the forming or moulding surface. The chamber or chambers may include the aforesaid foam material to support the sheet panel. Alternatively the chamber may contain a liquid to provide fluid support to the sheet panel. Preferably the chamber is a substantially closed chamber. Most preferably the chamber is substantially closed by means of a base member and thus can he of hollow box-like form.

The edges or surfaces of the supporting elements proximate the side of the sheet panel opposite the forming or moulding surface are suitably shaped such as by machining to have a profile which defines the required shape of the sheet panel. Thus when the sheet panel is secured to the supporting elements, the supporting elements ensure that the panel maintains the shape of its forming or moulding surface. Preferably the supporting elements are in the form of wall panels. The first and second pair of supporting elements thus suitably comprise side wall panels. Suitably the wall panels are formed of sheet material such as sheet metal and are of planar form. The base member may also comprise a planar panel such as a planar panel of sheet metal.

Preferably also, comer supports arc provided at each corner of the sheet panel. One or more corner supports may comprise legs which provide standing support for the sheet panel. Preferably the side wall panels extend between the comer supports. Preferably the corner supports are elongated and the side wall panels are secured to the comer supports. Preferably each co er support is provided with at least one longitudinally extending channel or track which can receive an end of a side wall panels. Preferably the end of the side wall panel is frictionally held to the corner support by engagement with the channel or track. The end of the side wall panel may also be secured by additional means to the comer supports. Thus where the side wall panels and comer supports are formed of metal, the ends of the side wall panels may be welded to the corner supports.

Alternatively or additionally, fasteners may be used to secure the side wall panels to the comer supports. Preferably the corner supports include a plurality of spaced longitudinally extending channels or tracks. The comer supports may be of a circular cross sectional configuration or any other cross sectional form and the channels are spaced around the comer supports. Typically the corner supports are formed as an extrusion such as an aluminium extrusion containing the channels or tracks.

The base member in the form of a panel may be located within the side wall panels to define with the side wall panels and sheet panel a substantially closed chamber. The base panel may have peripheral dimensional such that its sides are juxtaposed with the respective side wall panels. Means may be provided to secure or support the base panel to the corner supports. Such means may comprise stops secured to the corner supports with the base panel being seated on the comer supports. The corner supports may engage with a channel or track in the comer support. Alternatively, the base member may be secured or held to the comer supports and/or side panels by any other connecting arrangement such as a permanent connecting arrangemen The connecting arrangement where the panels and corner supports are metal may comprise welding. The substantially closed chamber may include the aforementioned foam material. The foam material may be injected into the chamber to expand therein.

5 Means may be provided for controlling the temperature of the at least one sheet panel. The temperature controlling means may comprise a cooling or heating element or coil secured to the sheet panel on the side of the panel opposite the shaping surface. The element may comprise an electrical element. The coil may be a tubing coil through which a cooling or heating gas or liquid may be passed.

Ϊ0 Where the chamber is to contain fluid, suitable sealing means may be provided to ensure that the chamber is sealed. The sealing means may comprise elongated seals between the sides of the base panel and side wall panels. The fluid may comprise a liquid constrained in the chamber and in contact with the side of the sheet panel opposite the

1 forming or moulding surface. Alternatively the liquid may be contained within a bladder or the like arranged within the chamber.

Means may be provided for controlling the temperature and/or pressure of the fluid. The temperature controlling means may comprise any known temperature controlling 0 apparatus such as liquid cooling apparatus. The pressure controlling means may comprise any means for increasing or decreasing the pressure of fluid in the chamber,

The forming or moulding surface of the tool may be defined by a plurality of shaped sheet panels, each having a forming or moulding surface with adjacent sheet panels 5 being arranged in an edge-to-edge relationship such that the forming or moulding surfaces of each sheet panel combine to define a composite forming or moulding surface for the forming or moulding tool. The supporting elements for the sheet panels such a Side wall panels as above are suitably provided at or along the boundaries or margins of each sheet panel and if necessary at other locations on the underside points of the sheet 0 panel. Each sheet panel with its supporting elements thus forms in effect a tool module. The side supporting elements such as side wall panels of each module may be juxtaposed with the side supporting elements or wall panels of adjacent modules or the side supporting element or wall panels of adjacent modules may be common with each other. Thus juxtaposed edges of adjacent sheet panels may be supported by a common side supporting element or wall panel of adjacent tool modules. The juxtaposed edges are suitably secured continuously such as by welding to the side supporting elements or wall panels.

The or each sheet panel may be formed or shaped into the required configuration to define the foπriing or moulding surface by any suitable forming or shaping process such as by a computer controlled process to ensure accuracy in the forming or shaping surface. Most preferably to enable rapid and inexpensive formation of the forming or moulding surface of a panel, the sheet panel is shaped to define the forming moulding surface in a single point incremental metal sheet forrning process known also as die-less forming process however the sheet metal panel may be shaped by any sheet metal forrning process. The edges or surfaces of the supporting elements which engage and support the sheet panel are shaped in any profiling process such as by machining suitably by a computer controlled process to ensure accuracy in the profile of the edge or surface.

Any suitable means may be provided to hold the sheet panels and thus respective f rming or mould ling surfaces in a juxtaposed attitude such that there is a relatively smooth transition between adjacent forming surfaces. The sheet panels may be joined along juxtaposed edges such as by welding where the panels are formed of sheet metal. Alternatively infill strips may be provided between adjacent sheet panels along the juxtaposed edges.

In yet a further aspect, the present invention provides a method of manufacturing ,a foπning or moxilding tool, said method including the steps of providing a plurality of sheet panels, shaping each said sheet panel to define a forming or moulding surface in said panel, and assembling said sheet panels relative to each other such that said forming or moulding surfaces of said sheet panels combine to define a composite forming or moulding surface of said forming or moulding tool,

Preferably the sheet panels are provided in tool modules and the method includes the step of assembling said modules relative to each other to position said sheet panels to define said composite forming or moulding surface.

Preferably the method includes the step of providing a plurality of supporting elements for said sheet panels, shaping said supporting elements such that said elements have profiled portions complementary to said shaped sheet panels and assembling said supporting elements such that shaped sheet panels arc received and supported by said complementary portions of said supporting elements.

The moulding or forming tools described above may be used both in an open or closed moulding process. For a closed mouldmg process, at least a pair of moulding or forming tools of the above described type are provided to form a mould assembly, the moulding or forming tools having moulding of forming surfaces defining the external shape of the article to be moulded. The mould tools are then arranged to cooperate typically in an opposing relationship such that the moulding or forming surface define a mould cavity in which the article can be moulded by any known moulding technique.

The present invention in yet a further aspect provides a method of moulding or foπning, said method including the steps of applying a formable material to the foπning surface of a foπning or moulding tool of the above described type such that the forrning material conforms to the shape of the forming or moulding surface of the tool. The formable material may be a liquid and/or solid material.

Brief Description of the Drawings ^•

In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention and wherein :-

Fig. I is a schematic plan view of a forming or moulding tool according to an embodiment of the present invention;

Fig. 2 is a cross sectional view of the forming or moulding tool of Fig. 1 ;

Figs. 3 and 4 are isometric views from above and below of a further embodiment of forming tool according to the invention; Figs. 5 and 6 are longitudinal and transverse isometric cross sectional views of the forming tool of Figs. 3 and 4;

Fig. 7 is a longitudinal cross sectional view of the forming tool of Figs. 3 and 4.

Fig. 8 is an underside view of a portion of the tool with a base panel shown shaded and in dotted outline;

Fig. 9 is an isometric sectional view of a closed mould assembly according to another aspect of the present invention; and

Fig, 1 is a longitudinal sectional view of the mould assembly of Fig. 9,

Detailed Description, of the Preferred Embodiment

Referring to the drawings and firstly to Figs.l and 2, there is illustrated schematically a forming or moulding tool 10 according to an embodiment of the present invention which in this instance defines a mould cavity 11 which is open on its upper side. The mould cavity 11 in the illustrated embodiment is generally oval in plan view and has a composite form rig of moulding surface 12 defining the boundaries of the mould cavity 11.

The tool 10 is of modular form and comprises a support structure 13 and a plurality of forming surfaces 14, adjacent forming surfaces 14 being juxtaposed in an edge-to-edge relationship and cooperating to define the composite forming surface 12. Each forming or moulding surface 14 is defined by a sheet panel such as a metal sheet 15 which may be formed or shaped into the appropriate configuration defined by the article to be produced with the tool to form the forming surface 14 by any sheet forming process. Typically, the metal sheet 15 is formed into the required configuration by a die-less metal sheet forming process such as by an incremental progressive metal sheet forming process.

In the illustrated embodiment of Figs. I and 2, the support structure 13 is an "egg-crate" structure comprising a plurality of substantially parallel longitudinally extending upright wall panels 16 and a plurality of substantially parallel transversely extending upright wall panels 17 which intersect the wall panels 16 at right angles and form with the wall panels 16 a supporting grid. The intersecting wall panels 16 and 17 define a plurality of hollow chambers 18 of box-like form and of rectangular cross section with the upper portion of each hollow chamber 18 being closed by the metal sheet 15 defining the forrning STJi c 14. The upper edges of the panels 15 and 16 conform to the shape of the undersides of the metal sheets 15. The lower edges of the panels 16 and 17 are coplanar and joined to a base 19. The hollow chamber 18 beneath each sheet 15 is defined by portions of the upright side wall panels 16 and 17 which extend upwardly from the base 19 to the formed sheet 1 to define a modular structure. Typically the side wall panels 16 and 17 may be manufactured from sheet metal or other sheet material which is profiled to match with the formed shape of the underside of the metal sheets 15 defining on their upper side the foπning surfaces 14. The base 19 may also be cut from sheet metal or other sheet material. Where the side wall panels 16 and 17 are formed of metal sheet, the edges of the metal sheets 1 are secured continuously by welding along to the upper edges of the panels 16 and 17. This ensures that the forming sheets 15 retain their required shape.

Whilst the "egg-crate" support described above provides side wall panels 16 and 17 which extend along and support the four side edges of the forming sheets 15, additional intermediate wall panels such as the wall panels 16' and 17' which extend parallel to the side wall panels 1 and 17 may be provided between the side wall panels 16 and 17 as shown in dotted outline in Fig. 1 - The intermediate walls 16' and 17' provide additional support to the metal sheets 15 at locations between the side wall panels 1 and 17 to provide increased stability to the moulding or forming surfaces 14. As with the side wall panels 16 aod 17, the upper edges of the intermediate panels 16' and 17' are profiled to match the formed profile in the metal sheets 15 where they meet the metal sheets 15. The intermediate panels at their upper edges may be joined to the underside of the metal sheets by stitch welding which will serve to hold the forming sheets 15 in their correct moulding shape.

Any other suitable means may be provided to give additional support to the metal sheets 5 and thus the mould surfaces 14 from the underside in additional to the "egg-crate" support. In the embodiment of Figs. 1 and 2, the sheets 15 may be supported hydraulically by fluid 20 contained within the chambers 18 defined by the forming sheets 15, side wall panels 16 and 17 and base 19. The fluid 20 will thus provide coxinteracting pressure supporting the forming surfaces 14 during a subsequent moulding process using the tool 10. Alternatively, the metal sheets 15 and thus the forming surfaces 14 may be supported by foam material. For example an expandable foam plastics material such as polyurethane foam may be injected into and fill the chambers 18. Alternatively or additionally, other mechanical supporting arrangement may ^"be provided on the undersides of the sheets 15.

The sheets 1 which define the forming surfaces 14 may be held together in an end-to- ead relationship with adjacent sheets 15 and in the required position to define the composite foπning surface 12 by any suitable connection arrangement or an external constraint which holds the adjacent sheets 15 in a juxtaposed position. At the junctions between adjacent forming surfaces 14, the sheets 15 abut one another with the join between adjacent sheets 15 extending along and being supported by the underlying top edges of the wall panels 16 and 17. Tπfill strips may be provided between the adjacent sheets 1 or to span adjacent sheets 15 and cover the join between the forrning surfaces 14 to define a substantially smooth surface at the join. Provision of infill strips however is optional depending upon the finish required in the article to be formed using the tool 10. As an alternative, the abutting edges of the sheets 15 may be joined by a permanent joining method such as by welding with the joint between abutting edges being ground down or machined level with the forming surfaces 14 adjacent the join.

Figs. 3 to 8 illustrate schematically a forming or moulding tool 21 according to a further embodiment of the invention, the tool 21 having a mould cavity 22 with a mould surface 23 made up of a plurality of individual forming or moulding surface* 24. As with the previous embodiment, each forming surface 24 is defined by a sheet panel 25 typically a sheet metal panel which is shaped to define the forming surfaces 24 such as by an incrernenta progressive metal forming process. When the panels 25 are assembled relative to each other, the surfaces 24 combine to define the composite moulding or forming surface 23 of the tool 21. The panels 25 typically may comprise an aluminium sheet.

The panels 25 which define the forming surfaces 24 in this embodiment are supported by a series of regularly spaced upright corner supports or legs 26 which extend downwardly from the underside of the sheet panels 25 at junctions 27 (see Fig. 7) between adjacent panels 25. Each panels 25 is further supported along or adjacent to their side edges by upright side wall panels 28 and 29 which extend between adjacent upright supporting legs 26. For this purpose the legs 26 are provided with longitudinally extending channels 30 arranged around their periphery and opposite edges of the side wall panels 28 and 29 are receivable wittrϊn selected channels 30. The side wall panels 2S and 29 for example may be slidably received longitudinally within the channels 30 to be held fπctionally therein. The upper edges of the side wall panels

28 and 29 are shaped to be complementary to the lower surfaces of the panels 25 so as to mate therewith. The panels 28 and 29 may be held in their required position to the legs 26 by any suitably restraining or locking arrangement such as stops which span the channels 30 of the legs 26. Alternatively the panels 28 and 29 may be secured to the legs 26 by welding.

As is apparent in Figs. 5 to 7 the upper edges of the side wall panels 28 and 29 extend along the joins 31 between adjacent abutting panels 25 such that marginal portions of each panel 25 at the joins 31 are supported from the underside. Further bottom panels 32 extend between the legs 26 and the side panels 28 and 29 to define enclosed chambers 33 beneath the sheet panels 25. The bottom panels 32 as shown more clearly in Fig. 8 arc located within the side panels 28 and 29 and held in position near to the sheet panels 25 by fasteners or stops 32' secured to the comer posts 26. The stops 32' may be threaded into nuts captured within the channels 30. An expandable foam material is injected into the chambers 33 to substantially fill the chambers 33 and provide support to the metal sheets 25.

As an alternative or additionally, the chambers 33 may contain a liquid for providing support the sheet panels 25 and thus the forming surfaces 24. Any suitable sealing means such as sealing strips 34 (Fig. 4) may be provided between adjacent edges of the bottom panels 32 and between the panels 32 and side panels 28 and/or 29 where necessary to prevent escape of liquid from the chambers 33. Some liquid communication however can be permitted between adjacent chambers 33.

The chambers 33 in this embodiment are substantially smaller than the chambers 18 of the embodiment of Figs. 1 and 2 to reduce the volume of foam or liquid required to support the forming surfaces 24. This is achieved by positioning the bottom panels 32 close to the metal sheet panels 25 which define the foπning surfaces 24.

Assembly of the components of the tool 1 effectively forms a series of rectangular modules defined by a set of four legs 26, an upper panel 25 which defines a forming surface 24, opposite side wall panels 28 and 29 and a bottom panel 32 which combine to form a chamber 33 beneath each forming panel 25. Adjacent modules however have legs 26 which are common to each other and further have side wall panels 28 and 29 which, are common to each other. Where the chambers 33 are filled with a foam material, each module in effect comprises a sandwich composite construction with an upper forming or moulding panel 25 and lower bottom panel 32 with the supporting foam, material sandwiched therebetween.

Where liquid is used within the chamber 33 to support the metal sheets 25 and thus the forming surfaces 24, the liquid may be heated or cooled to vary the temperature of the mould forming surfaces 24. Alternatively and as shown in Fig. 8, a cooling ox heating coil 35 may be secured to the metal sheet panel 25 on the underside of the forming surface 24. The coil 35 comprises a coil of metal heat conducting tubing for example copper or aluminium tubing which is secured such as by welding to the panel 25. The coil 35 has an inlet 36 and an outlet 36' to enable the introduction of a heating or cooling liquid to heat or cool the forming surface 24 during a moulding process. The coils 35 of each module may be interconnected such that all forming surfaces 24 can be simultaneously heated or cooled. Alternatively only selected foπning surfaces 24 may be heated or cooled. An alternative to tubing for heating the panels may comprise an electrical heating element such as a flexible heating element or pad.

In use the tools 10 and 21 may be used for a range of different processes including open and closed moulding processes. In an open moulding process the tools 10 and 21 are used in the configuration described above. An example of an open moulding process is a vacuum forrning process where a thin sheet of material may b laid over the tool 10 or 1 and drawn under the influence of a vacuum into the mould cavity to conform to the shape of the mould surfaces 14 or 24. In another example of an open moulding process, the mould tools 10 and 21 may be used in a glass reinforced plastics or other composite material moulding process with the mould surfaces 14 or 24 defining the external shape of the product to be manufactures such as the hull of a. watercraft. Moulding of the product is carried out in conventional fashion by the application of a release agent and gel coat to the mould surfaces 12 or 23 followed by the application of layers of reinforcing glass cloth and resin.

During a moulding or forming process using the tool 21, the sheet panels 25 are supported by the panels 28 and 29 in the egg-crate configuration, foam or liquid within the chambers 33 and the bottom panels 32. Load applied to the bottom panels 32 is transferred through the stops 32' to the legs or corner supports 26 so that distortion of the forming panels 25 is resisted.

For the purposes of using tools in accordance with the invention in a closed moulding process, a pair of cooperable mould tools of the above described construction are employed. An example of a mould assembly 37 for use. in a closed moulding comprising a pair of cooperating upper and lower mould tools 38 and 39 is shown in Figs. 9 and 10. The moutd tools 38 and 39 are of similar construction to the tool described with reference to Figs. 3 to 8 and comprise (with reference to the upper mould tool 38) a plurality of mould modules 40 each of which has a forming Or moulding surface 41 with the respective surfaces 41 of the mould modules 40 combining to form a composite mould surfaces 42 for the mould tool 38. As in the previous embodiments the mould modules 40 comprise a sheet metal panel 43 shaped to define a forrning surface 41, opposite pairs of side panels 44 and 45 which extend to and support the panel 43 adjacent its side edges, the side panels 44 and 45 being connected to corner supports 46 at each comer of the panel 43, the supports 46 being of the same configuration as the legs 26. Some of the supports 46 may terminate in a common plane so as to act as legs whilst some of the supports 46 may be of a reduced length.

A base panel 47 is connected to the side panels 44 and 45 at a position spaced from the forming panel 43 to define a hollow chamber 48, The panel 43 may also carry on its rear side a cooling or heating coil 49 similar to the coil 35 described with reference to Fig. 8. The lower mould tool 39 is of a similar construction to the upper mould tool 38. The upper and lower mould tools 38 and 39 are assembled relative to each other in an opposing relationship such that a mould cavity defining the shape of the product to be moulded is formed between the respective mould surfaces of the mould tools 38 and 39.

Conventional sealing arrangements including vacuum sealing arrangement (not shown) are provided between the opposing marginal faces of the upper and lower mould tools 38 and 39 so as to seal the mould cavity for the subsequent moulding process. In addition any know arrangement may be provided for aligning the upper and lower mould tools 38 and 39 to define the mould cavity.

The mould assembly 37 may be used for example in a conventional Resin Transfer Moulding (RTM) process wherein a fiber mat is initially provided in the mould cavity being usually clamped at its edges between the upper and lower mould tools 38 and 39. Catalysed resin is the injected into the mould cavity under pressure to form to the shape of the product as determined by the moulding surfaces of the upper and lower moulds 38 and 39. The tools may also be used in Reaction Injection Moulding processes by injecting reactive components into a mould cavity defined by a mould assembly formed in a similar manner to the mould assembly 37.

The chambers 48 are filled with a foam material such as foam plastics material or a ceramic or metal foam to support the mould panels 43. A heated liquid or gas can he passed through the coils 49 of all the mould modules or selected mould modules 40 to assist in curing the resin.

In an alternative arrangement, the hollow chambers 48 of the mould tools 38 and/or 39 may contain a fluid to support the module foπning surfaces 41 as well as providing even support to the whole mould surface 42 enabling the temperature of the tool to be controlled by heating or cooling of the fluid.

In the above described embodiments, and where fluid is employed to support the forming surfaces and resist loading therein, the fluid as in the previous embodiments is contained in chambers 48. In an alternative arrangement, fluid may be provided in flexible containers such as flexible bladders which are located in the chambers beneath the farming surfaces. Such an arrangement enables the pressure and or temperature of fluid adjacent each fonning surface to be individually controlled by simply varying the pressure and or temperature of fluid in the bladder.

Tools in accordance with the present invention may be manufactured relatively simply at a relatively low cost and at a fast delivery time. As the tools are of modular form, they may be easily assembled and disassembled and transported and stored away. In addition, the tools having their forming surfaces formed by sheet material aro light and rigid.

Whilst the mould panels such as the mould panels 25 are of rectangular or square plan view for convenience and ease of construction, they may be of other peripheral form in plan view for example of triangular form.

Whilst the forming surfaces of each module are preferably supported along or adjacent their side edges by the upright side walls and/or legs, they may additionally or alternatively be supported between their edges by intermediate upright walls, legs or any other supporting structure.

Usually a plurality of tool modules are provided however in the case of small components, only one tool module may be may be required to manufacture the tool. For complex tools surfaces, the modules may be stacked three dimensionally to form for example vertical faces.

The preferred method of forming the module forming surfaces is to use a single point incremental/progressive metal sheet forming process which in most cases eliminates the need of a die or plug to form the shaped surface. No complex machining of the tool surface is required and all components can be manufactured using metal sheet cutting and die-less forming technologies.

The terms "comprising" or "comprises" as used throughout the specification and claims are taken to specify the presence of the stated features, integers and components refeπed to but not preclude the presence or addition of one or more other feature/s, integer/s, component/s or group thereof.

Whilst the above has been given by way of illustrative embodiment of the invention, all such variations and modifications tliereto as would be apparent to persons skilled in the art are deemed to fell within the broad scope and ambit of the invention as defined in the appended claims.

Claims

1. A forming or moulding toot having a forming or moulding surface defined by at least one shaped sheet panel and support means for supporting said sheet panel and thereby said forrning or moulding surface.

2. A tool as claimed in claim 1 wherein said support means for said at least one sheet panel comprises mechanical and/or fluid supporting means arranged on the side of the sheet panel remote from the forming or moulding surface.

3. A tool as claimed in claim 2 wherein said mechanical supporting means comprise an egg-crate support for supporting the sheet panel at a plurality of locations.

4. A tool as claimed in claim 2 or claim 3 wherein said mechanical supporting means include a foam material.

5. A tool as claimed in claim 3 wherein said egg-crate support comprises a plurality of supporting elements arranged in a grid .

6. A tool as claimed in claim 5 wherein each said supporting element has an edge or surface complementary to portion of the side of the sheet panel opposite the forming or moulding surface such that the portion of the sheet panel is supported continuously along the edge or surface of the supporting element.

7. A tool as claimed as claim 6 wherein said supporting elements for the or each said sheet panel comprise at least a first supporting element and a second supporting element extending substantially normal .to the first supporting element.

8. A tool as claimed in claim 7 wherein said supporting elements comprise a pair of spaced apart first supporting elements and a pair of spaced apart second supporting elements, the elements of each pair extending substantially parallel to each other.

9. A tool as claimed in claim 8 wherein the or each said sheet panel is rectangular in plan view and wherein said first and second pairs of supporting elements extend along and support the side edges of the sheet panel.

10. A tool as claimed in claim 9 and including intermediate supporting elements between the elements of the first and second pairs for supporting intermediate portions of said sheet panel.

11. A tool as claimed in claim 9 or claim 10 wherein said sheet panel is secured continuously along its side edges to the respective supporting elements of said first and second pair.

12. A tool as claimed in claim 11 wherein said sheet panels and supporting elements are formed of metal, said sheet panels being secured to the supporting elements by welding.

13. A tool as claimed in any one of claims 9 to 12 wherein said sheet panel and supporting elements define a chamber or chambers on the side of the sheet panel opposite the forming or moulding surface.

14. A tool as claimed in claim 13 wherein said chamber or chambers include foam material to support the sheet panel.

15. A tool as claimed in claim 13 wherein said chamber contains a liquid to provide hydraulic support to the sheet panel.

16. A tool as claimed in any one of claims 13 to 15 wherein said chamber is a substantially closed chamber.

17. A tool as claimed in any one of claims 5 to 16 wherein said supporting elements comprise wall panels formed of sheet material.

18. A tool as claimed in claim 17 and including corner supports provided at each corner of the sheet panel, said wall panels extending between the corner supports.

19, A tool as claimed in claim 18 wherein said corner supports are elongated and wherein said side wall panels are secured to the corner supports.

20. A tool as claimed in claim 19 wherein each corner support is provided with at least one longitudinally extending channel or track for receiving an end of a side wall panel.

21. A tool as claimed in any one of claims 17 to 20 and including a base panel located within the side wall panels to define with the side wall panels and sheet panel a substantially closed chamber.

22. A tool as claimed in claim 21 and including means for supporting said base member to said corner supports.

23. A tool as claimed in claim 22 wherein said supporting means include stops secured to said comer supports, said base panel being seated on said stops.

24. A tool as claimed in any one of the preceding claims and including means for controlling the temperature of said at least one sheet panel.

25. A tool as claimed in claim 24 wherein said temperature controlling means comprises a heating and/or cooling element secured to said panel.

26. A tool as claimed in any one of the preceding claims wherein said forming or moulding surface is defined by a plurality of shaped sheet panels, each having a forming or moulding surface, adjacent sheet panels being arranged in an edge-to-edge relationship such that the forming or moulding surfaces of each sheet panel combine to define a composite forrning or moulding surface for the forming or moulding took

27. A tool as claimed in claim 26 wherein said support moans define common supports for the juxtaposed edges of adjacent sheet panels.

28. A tool as claimed in claim 26 or claim 27 wherein said juxtaposed edges are secured continuously to the common supports.

29. A tool as claimed in any one of the preceding claims wherein said panels comprise metal panels shaped in a single point incremental metal sheet forming process,

30. A tool as claimed in any one of claims 26 to 29 wherein juxtaposed edges of said sheet panels are joined by welding.

31. A method of manufacturing a formin or moulding tool, said method including the steps of providing a plurality of sheet panels, shaping said sheet panels to define a forming or moulding surface in said sheet panel, and assembling said sheet panels relative to each other such that said forming or moulding surfaces of said sheet panels combine to define a composite forming or moulding surface of said forming or moulding tool.

32. A method as claimed in claim 31 wherein said sheet panels are provided in tool modules, said method including the step of assembling said modules relative to each other to position said sheet panels to define said composite forming or mouldmg surface.

33. A method as claimed in claim 31 or claim 32 and including the step of providing a plurality of supporting elements for said sheet panels, shaping said supporting elements such that said elements have profiles complementary to said shaped sheet panels and assembling said supporting elements such that portions of said shaped sheet panels are received and supported by said complementary portions of said supporting elements.

34. A mould assembly including at least one pair or moulds or tools of the type defined in any one of claims 1 to 30, said moulds or tools cooperating to define between said moulding or forming surfaces a mould cavity,

35. A method of moulding or forming, said method including the steps of applying a formable material to the forming surface of a forming or moulding tool of the type defined in any one of claims 1 to 30 such that the foπning material conforms to the shape of the foπning or moulding surface of the tool.